Vitamin A is responsible for the health and maintenance of the mucous membrane (the inner skin of the body). A deficient membrane is susceptible to infections, pollution and irritation, catarrhal formations, allergic reactions, and deformation. Similarly, epithelial skin is dependent upon vitamin A for healing and resistance to acne. Though potentially toxic in high doses (usually achieved through synthetic mega-doses for a sustained period of time), nutritional levels of natural Vitamin A is never toxic.

According to Harvard University's Recent Nurses' Health Study, vitamin A may reduce the risk of breast cancer. Its precursor present in many plants, beta carotene, may also reduce the risk of some cancers. The latest good news, according to a Johns Hopkins School of Medicine study conducted in Africa, is that vitamin A and beta-carotene (and possibly other carotenoid vitamin A precursors) may reduce the transmission of AIDS from mother to infant.